Pathology of sudden infant death syndrome.

This study is based on 15 cases examined by the author. The majority of the infants were found in a prone position. Thymus was enlarged in all cases. Its enlargement of the lower portion overlying the basal portion of the heart formed an unyielding, tense membrane. In prone position, the heavy ventricles fell forward, producing angulation and kinking against this membrane and inhibited the filling of the heart or irritated the heart, producing arrhythmia and cardiac arrest.